Fan Unit and Its Mounting

ABSTRACT

In a method of mounting cooling air fans ( 2 ) in an electronic equipment unit ( 3 ) having a unit front ( 4 ) a unit rear ( 5 ) and unit sides ( 6, 7 ) and wherein the cooling air fan/fans produce cooling air flow (AF) directed from the unit front to the unit rear, cooling air fans are attached to a flexible cooling air fan carrier ( 8 ) that is introduced through a slot ( 3 A) in the unit front and is advanced along a non-linear path ( 9 ). The cooling air fan carrier is advanced along a first, generally straight path section ( 9 A) from the unit front and approximately to the unit rear, further through a second, bent path section ( 9 B) and through a third, generally straight path section ( 9 C) extending along the unit rear, thereby positioning the cooling air fans along the unit rear.

TECHNICAL FIELD

The present invention generally concerns the cooling of electronic equipment and specifically relates to cooling fans that are mounted in electronic equipment units.

BACKGROUND

Most electronic equipment units require appropriate internal cooling to function properly. Examples thereof are electronic equipment units, mostly rack mounted, comprising a case or housing enclosing various electronic components and intended for use within e g the field of telecommunication. For such electronic telecommunication equipment units there are different cooling standards in different regions of the world. Specifically, in some regions it is acceptable to perform cooling by providing lateral cooling air flow, in other words cooling air flow from one side of the unit to the other side. Also, in such regions the input side may differ. On the contrary, only front cooling, in other words a front end to rear end cooling air flow, is accepted by all significant regions, including USA, EU and Asia.

It is also a general fact that electronic equipment units having different cooling philosophies should not be mixed. It is therefore a well established fact that in order to provide a cooling system that is common to most regions, the direction of the cooling air flow must be from a front end to a rear end of the unit.

To provide such a front-to-rear cooling air flow with the existing solutions, fans may either be mounted directly at the front end of the unit to force cooling air flow from the front end to rear end of the unit. Alternatively, the fans may be mounted at the rear end of the unit to draw cooling air flow from the front end to the rear end of the unit. A front end mounting has the accompanying disadvantage that a significant portion, up to approximately 25%, of the front end space is occupied by the fans. This significantly reduces the useable space for front connectors. Rear end mounting of the fans normally requires that the fans may be easily accessed from the rear end of the unit during normal operation. In the alternative, the complete unit would need to be powered off and disconnected before the fans can be replaced. This would in turn result in longer interruptions of operation, which would be an extremely inappropriate consequence.

SUMMARY

A general object of the present invention is to provide a solution to the described problems.

A specific object is to provide an improved method of cooling fan mounting in an electronic equipment unit.

Another specific object is to provide an improved cooling fan assembly for cooling an electronic equipment unit.

Yet another specific object is to provide an improved electronic equipment unit with front-to-rear cooling air flow.

These, as well as other objects are met by embodiments defined by the accompanying patent claims.

The invention relates generally to electronic equipment units having a unit front, a unit rear and unit sides. Cooling air flow is directed from the unit front to the unit rear by at least one cooling fan that is mounted in the unit. In a basic configuration an application dependent number of cooling fans are attached to a flexible fan carrier that is introduced through the unit front. The carrier is then advanced along a non-linear path, along a first straight section from the unit front to the unit rear, further through a second, bent path section and through a third, straight path section along the unit rear, thereby positioning the fan/fans along the unit rear.

This basic inventive configuration presents the advantages of:

-   -   quick, simple and effective cooling fan mounting and         replacement;     -   minimized disturbance of operation by fan replacement;     -   cooling fan replacement not requiring rear access; and     -   practically no occupation of front end space.

Advantages offered by the present invention, in addition to those described, will be readily appreciated upon reading the below detailed description of embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention and its further objects and advantages will be best understood by reference to the following description taken together with the accompanying drawings, in which:

FIG. 1 is a schematical perspective view of a common type of prior art electronic equipment unit with front-to-rear cooling air flow;

FIG. 2 is a partial and schematical perspective view of an embodiment of a cooling fan assembly of the invention;

FIG. 3 is a schematical top view of an electronic equipment unit of the invention, for use with the cooling fan assembly of FIG. 2;

FIG. 4 is a front view of the electronic equipment unit of FIG. 3; and

FIG. 5 is a schematical perspective view of an electronic equipment unit of the invention, illustrating the mounting of a cooling fan assembly as shown in FIG. 2 therein.

DETAILED DESCRIPTION

A cooling fan assembly of the invention as well as the mounting thereof in an electronic equipment unit will be explained with reference to an exemplifying embodiment that is illustrated in the accompanying drawing FIGS. 2-5. It is emphasized that these illustrations have the single purpose of describing an exemplary embodiment of the invention and are not intended to limit the invention to the details thereof. Said embodiment relates to an application of the inventive solution to an electronic equipment unit of a type commonly used within the telecommunications field, but may likewise be used for electronic equipment units for use in other fields.

In FIG. 1 is outlined an example of such an electronic equipment unit 103 of a general rack mounted type that was described in the introduction and to which the invention may be applied. Briefly, such a prior art electronic equipment unit 103 consists of a housing having a unit front 104, a unit rear 105 and unit sides 106, 107. Conventionally, the unit front 104 has multiple front connectors 120 of optional types that are appropriate for a specific unit 103 application and a power supply connector 121. The illustrated prior art electronic equipment unit 103 is of the conventional front to rear cooling type where a cooling fan assembly 101 comprises fans 102 that are mounted at the unit front 104 to suck in cooling air through louvers 102A provided in a housing plate of the actual unit front 104. In operation, cooling air is introduced into the unit 103 by the fans 102 and through the corresponding louvers 102A to provide the desired front to rear cooling air flow AF. It will be clearly appreciated from FIG. 1 that such a cooling fan assembly 101 configuration will significantly affect the available connector space in the unit front 104. Such front mounted fan assembly 101 configurations have been very commonly used, but as was discussed above alternative configurations with rear mounted fans have also been fairly common. The rear mounted fan configurations suffer from the initially discussed drawback of requiring access to the unit rear 105 in situations requiring fan replacement during operation.

The invention intends to solve the problems that were briefly discussed above as well as in the introduction. Such problems relate to the combination of achieving appropriate, efficient cooling of the electronic equipment units and of securing optimized practical use thereof. To overcome the shortcomings and problems associated with the conventional cooling fan configurations, a new concept is proposed for mounting the fans in the units. A basic feature of this solution is the provision of a path through the unit, for introducing fans from a very restricted opening in the unit front and to a working position along the unit rear.

This inventive concept enables practical and efficient use of essentially the entire unit front for connectors of the required type and number. Still, this concept additionally enables practical and quick fan replacement from the unit front. Fan replacement is allowed during equipment operation and yet no access to the unit rear is required during such operation. It is presently estimated that dismounting of used fans and mounting of new fans will take less than 1 minute.

In FIGS. 3-5 is illustrated an exemplary embodiment of an electronic equipment unit 3 of the common, above described type, to which the basic concept of the invention has been applied. Specifically, this embodiment of the electronic equipment unit 3 has been configured for receiving a cooling air fan assembly 1 that is partially illustrated in detail in FIG. 2. The cooling air fan assembly 1 is intended for providing a front to rear cooling air flow AF in the electronic equipment unit 3 and comprises cooling air fans 2 supported on an elongated flexible cooling air fan carrier 8 having spaced attachments 11 for receiving an optional number of said cooling air fans 2 in a row along a portion of the carrier 8. The actual carrier 8 consists of an elongated strip of a suitable resilient or bendable material. It may preferably, but not exclusively be formed of standard PCB substrate material.

In the illustrated embodiment the fan attachments 11 each comprise a fan inlet opening 11A that is aligned with the fan rotor 2B and through which cooling air is sucked to be discharged through fan outlet perforations 2C (see FIG. 5) in the unit rear 5. Each fan attachment 11 also comprises a number of holes 11B, here four, for receiving fasteners (not specifically shown) by means of which the fans 2 are secured to the carrier 8. The fasteners may be screw type fasteners or any other type of fastener that is commonly used in this type of environment. Fans 2 are attached to the carrier 8 starting from an end thereof that is intended to be introduced first into the unit 3 in the manner described below. Fans are also attached thereto over a length of the carrier 8 that in the fully introduced position of the carrier 8 is positioned along the unit rear 5. The remaining length of the carrier 8 is normally free from fans 2 and fan attachments 11.

This carrier 8 of the cooling fan assembly 1 may additionally have articulated joints 13 provided at regular distances along the carrier 8 to further facilitate the later described introduction of the carrier 8 into the unit 3. In applications requiring more than one fan 2 such articulated joints 13 may be provided at least between each of said spaced attachments 11 for the fans 2. Articulated joints 13 of this kind may also be provided in a portion of the carrier 8 being adjacent to a last fan 2 of a row, as seen in the later described direction of carrier 8 introduction into the unit 3, and even in portions of the carrier 8 not supporting any fans.

The carriers 8 are further provided with connectors that are generally designated by the reference number 12 and that are only very schematically illustrated in FIG. 2. The purpose of the connectors 12 is to enable powering of the fan or fans 2 by connecting each of them to a power supply (not shown) through a power rail 14 provided in the carrier 8 material. In the illustrated embodiment the connectors 12 are further attached to a partly cut-out or sliced section 8A of the carrier 8 material. These sliced sections 8A are formed in the area of the articulated joints 13 and serve to reduce stress on the connectors 12 when the carrier 8 is bent during insertion through the later described non-linear introduction path 9. The same connectors 12 may preferably also be employed to provide controlling and/or monitoring of the fans 2. This is done by returning tachometer signals from each fan 2 through the carrier 8 in a manner that is not specifically shown but that would be obvious to a skilled practitioner within this field, not least in the case where the carrier is formed of standard PCB substrate material. The carrier 8 and/or its power rail 14 is connected to a motherboard 25 of the unit 3 by means of a standard type connector or cable 15, as is vaguely indicated in FIG. 3. Thereby, the power rail 14 and/or the separate tachometer signals are connected and transmitted, respectively, to the appropriate power supply means and control/monitoring means, respectively, using standard technology, such as that used for normal fan units.

As was mentioned above, the electronic equipment unit 3 disclosed in FIGS. 3-5 is adapted specifically for use with the cooling fan assembly 8 of the invention. Like the common unit of this type, shown in FIG. 1, it has the unit front 4, unit rear 5 and unit sides 6, 7 and directs cooling air flow AF generally from the unit front 4 to the unit rear 5. In the unit front 4 is provided a small introduction slot 3A that opens into a non-linear path 9 for the introduction of a cooling fan assembly 1 as described above with reference to FIG. 2. It will be noted, especially in FIG. 4, that the unit front 4 space available for front connectors 20 is only restricted by the small introduction slot 3A and a number of narrow air inlet openings 2A that may be provided so as to not significantly interfere with the front connector 20 space.

The path 9 for the unit front 4 to unit rear 5 introduction of the cooling fan assembly 1 with its carrier 8 and fans 2 consists of a first, generally straight path section 9A extending from the unit front 4 and approximately to the unit rear 5, a second, bent path section 9B and a third, generally straight path section 9C extending generally along the unit rear 5. It will be realized that the second bent path section 9B interconnects said first and third path sections 9A and 9C, respectively, to provide a substantially uninterrupted non-linear guide path 9 for the safe guiding of the cooling fan assembly 1 from front to rear.

In particular, the non-linear path 9 may be formed between appropriately spaced, generally parallel walls 10A, 10B, 10C provided inside the electronic equipment unit 3 and extended along a unit side 6, at a rear corner of the unit 3 and along the unit rear 5, respectively. As will be seen in FIG. 5, an inner wall of the walls 10C forming the third path section 9C is provided with cooling air inlet openings 16 that are generally aligned with associated fan outlet perforations 2C in the unit rear 5. It should be noted that for a strict front to rear cooling the fans 2 and their fan attachments 11 are restricted to a portion of the carrier 8 that corresponds to the unit rear 5 when the carrier is completely introduced. Also, it should be obvious that the carrier 8 has such a length that when fully inserted into the path 9, it may still be gripped at the unit front 4 for withdrawal from the unit 3.

From the above description of FIG. 2-5 it should now be clear that the invention is also concerned with a method for mounting cooling fans 2 in an electronic equipment unit 3 having a unit front 4, a unit rear 5 and unit sides 6, 7 and wherein the fan/fans produce cooling air flow AF directed generally from the unit front 4 to the unit rear 5. According to the invention cooling fans 2 in a number being appropriate for a specific electronic equipment unit application are attached to a flexible fan carrier 8. The flexible fan carrier 8 is then introduced through the designated slot 3A in the unit front 4 and is advanced along the non-linear path 9. Thereby the flexible fan carrier 8 is initially advanced along the first, generally straight path section 9A from the unit front 4, along a unit side 6 and approximately to the unit rear 5. The fan carrier 8 is then advanced further through the second, bent path section 9B and finally further through the third, generally straight path section 9C extending along the unit rear 5. It will now be realized that the cooling fans 2 are attached to the carrier 8 starting from one end thereof that is intended to be first introduced into the unit 3 path 9, so that, being fully inserted into the path 9 the fan carrier 8 positions the appropriate number of fans along the unit rear 5.

As was described above, the non-linear path 9 is formed between appropriately spaced, generally parallel walls 10A-10C that are attached inside the electronic equipment unit 3. In situations requiring replacement of cooling fans 2 being supported by an existing fan carrier 8 in position in an electronic equipment unit 3, the carrier 8 having said fans 2 is simply withdrawn from the non-linear path 9 and is pulled out through the unit front 4 slot 3A. Obviously the assembly 1 connection/connections 15 to the motherboard 25 are first disconnected. A new carrier 8 with attached fans 2 is then introduced through the slot 3A, is pushed into position along the non-linear path 9 and is connected to the motherboard 25.

Powering of the fan/fans 2 is preferably enabled by connecting them to an appropriate power supply (not shown) through the carrier 8. To further optimize the cooling performance of the cooling fan assembly 1, controlling and/or monitoring of the fans is preferably also enabled by connecting them to the appropriate control and/or monitoring means through the carrier 8. The design of such control and/or monitoring means and the practical connection between such means and the fans is not specifically shown or described herein since it is considered to fall within the ordinary skill of a practitioner within this field.

In alternative, but not specifically illustrated embodiments of the invention, variations of the illustrated cooling fan assembly and electronic equipment unit according to the invention may be employed without departing from the scope of the invention. To exemplify this, the carriers may be specific for each application, with their fan attachments optionally distributed along the carrier to suit the specific application or may alternatively be standardized, having the fan attachments equally separated, regularly or evenly distributed along the carrier. In other words, the cooling fans may be attached to a flexible fan carrier in a number being appropriate for a specific electronic equipment unit application. In such variations, depending upon the actual application requiring one or several cooling fans in the electronic equipment unit, special carriers may therefore either be provided with an appropriate number of fan attachments for the different numbers of fans or superfluous fan attachments of a standardized carrier may be blocked.

The invention has been described in connection with an embodiment that is to be regarded as an illustrative example of the invention. It will be understood by those skilled in the art that the invention is not limited to the disclosed embodiment but is intended to cover various modifications and equivalent arrangements. The invention likewise covers any feasible combination of features described and illustrated herein. The scope of the invention is defined by the appended claims. 

1-10. (canceled)
 11. A method of mounting one or several cooling fans in an electronic equipment unit having a unit front, a unit rear, and unit sides, and wherein the one or several cooling fans produce cooling air flow directed generally from the unit front to the unit rear, the method comprising: attaching the one or more cooling fans to a flexible cooling air fan carrier, in a number that is appropriate for a specific electronic equipment unit application; introducing the cooling air fan carrier with the attached cooling fans through a designated slot in the unit front; advancing the cooling air fan carrier with the attached cooling fans along a non-linear path within the unit, by advancing the cooling air fan carrier along a first, generally straight path section from the unit front and approximately to the unit rear, advancing the cooling air fan carrier through a second bent path section, and advancing the flexible cooling air fan carrier along a third, generally straight path section extending along the unit rear; and positioning the one or more cooling fans along the unit rear.
 12. The method of claim 11, further comprising: connecting power, or control signals, or monitoring signals, or some combination thereof, to the cooling air fan carrier.
 13. The method of claim 11, further comprising forming the non-linear path between appropriately spaced, generally parallel walls inside the electronic equipment unit.
 14. The method of claim 11, further comprising replacing cooling air fans by withdrawing an existing cooling air fan carrier supporting said cooling air fans from the non-linear path and through the unit front slot and by introducing a new cooling air fan carrier with attached cooling air fans through the slot and into the non-linear path.
 15. A cooling air fan assembly for providing a cooling air flow in an electronic equipment unit, said cooling air fan assembly comprising: a flexible cooling air fan carrier having spaced attachments for receiving a plurality of cooling air fans.
 16. The cooling air fan assembly of claim 15, characterized in that the cooling air fan carrier has connectors for connecting each of the cooling air fans for controlling the cooling air fans, monitoring the cooling air fans, or powering the cooling air fans, or some combination thereof.
 17. The cooling air fan assembly of claim 15, wherein the cooling air fan carrier has articulated joints between each of the spaced attachments for the cooling air fans.
 18. The cooling air fan assembly of claim 15, wherein the cooling air fan carrier is formed by a standard printed circuit board substrate.
 19. An electronic equipment unit having a unit front, a unit rear, and unit sides, and adapted for the flow of cooling air generally from the unit front to the unit rear, the electronic equipment unit comprising: an introduction slot in the unit front, said slot opening into a non-linear path for the introduction of a cooling air fan assembly, said path having a first, generally straight path section extending from the unit front and approximately to the unit rear, a second, bent path section and a third, generally straight path section extending along the unit rear.
 20. The electronic equipment unit of claim 19, wherein the non-linear path is formed between appropriately spaced, generally parallel walls provided inside the electronic equipment unit. 